People aren't really switching from GL to vk for performance reasons. If you were able to get a full AZDO OpenGL environment everywhere you would probably be ge

People aren't really switching from GL to vk for performance reasons. If you were able to get a full AZDO OpenGL environment everywhere you would probably be getting better frames from that (since a lot of driver performance optimization in vk is pushed on the user, and the GL drivers are more mature). Problem is you cannot get anything close to that on any reasonable sampling of OpenGL platforms, in anything close to working condition. At best you just end up using the degenerate subset of APIs that can actually work across all your targeted systems - for a fully cross-platform title, that would include Android, and probably limit you to OpenGL ES 2. If you drop mobile, it would be around OpenGL 3.1-3.3. If you throw out some hardware as new as 2012, you could get stuck at Apple's last supported (which is buggy and broken all the same) OpenGL at 4.1. You can throw out Apple, and get stuck at recent Windows AMD and Intel support around 4.2. But that is the best case - where you don't then pick your target and find out all the drivers are broken in a dozen different ways each for the extensions you are using. It is only OpenGL 4.4 and 4.5 that Khronos has required conformance testing for certification for, and very few people are targeting those for development because of how limited a subset of the market actually supports them. So that is the point where you throw the whole mess out and just use Vulkan - which only has one major release version, and has 3 feature support levels you can pick from, with conformance testing for all of them.